Enhanced uplink, also known as High-Speed Uplink Packet Access (HSUPA), has been introduced into wireless communication standards (e.g., standards developed through the 3rd Generation Partnership Project (3GPP)). In HSUPA, a user equipment (UE) may transmit data in the uplink (i.e., to a base station, such as a NodeB) using a channel knows as the Enhanced Dedicated Channel (E-DCH).
For HSUPA, a scheduler component of the base station is a key element because it decides when and at what data rate a UE is allowed to transmit. The scheduler makes its decision based on, among other things, the state of the transmission buffers of the UEs in communication with the base station. Accordingly, there is a mechanism for each UE in communication with the base station to transmit to the base station buffer status information and/or other information that can be used by the base station to, for example, make scheduling decisions. Such information transmitted to the base station by the UE is referred to as scheduling information (SI).
Dual Cell HSUPA (DC-HSUPA) is an extension of HSUPA. In DC-HSUPA, a UE may use two or more different E-DCH channels to transmit its data to the network. One of the E-DCH channels is the primary (or anchor) channel and the other channels are secondary channels. Hence, in DC-HSUPA, the UE may send SI using the primary channel and a secondary channel.